The continuous supply of a coolant to the interface of a cutting tool and a workpiece in a machine tool is a single example of a situation where the supply of a liquid must be reliable as to clarity and continuity. The term "clarity" is used herein to denote a liquid which is sufficiently free from solid material that it can safely and effectively be applied to a user device without damage, for example as a coolant supplied to the interface of a workpiece and a cutting tool.
At first glance this would seem to be a simple matter, but in fact it is quite complicated. Metal cutting operations require coolants not only sufficient to cool and lubricate the tool-workpiece interface, but also to flush away the cuttings. While some cuttings such as turnings can be screened out, others such as chips and smaller particulates cannot be, at least to the extent that the coolant can immediately be recirculated to the interface. Beyond this, such systems tend to be subject to sludge build-up with its accompanying odors and the resulting need to dump the coolant from time to time. Disposal of coolant is an increasing economic burden.
A practical continuous flow system cannot work without a surge tank which can accommodate occasional abrupt increases and decreases in demand. Also, machine tools cannot tolerate interruptions in the supply of coolants, because the part being manufactured is likely to be adversely affected. Especially in shops where there are many tools, the trend is to provide a central coolant supply and plumb the machines to it. This is cumbersome and expensive.
It is an object of this invention to provide a coolant system which can be utilized by only one, or by many machine tools, in which a coolant to be recirculated is suitably and continuously clarified, and in which there is no build-up of sludge or particulates, these being continuously removed in a system wherein the total volume of the coolant is kept "live".